1. Field of the Invention:
This invention relates to a radiowave absorber and its manufacturing process.
2. Description of the Prior Art:
A radiowave absorbing body is a material which absorbs a radio wave falling on it and dissipates its energy by converting it to heat, so that no reflected wave may be produces. Various types of radiowave absorbers are used for various purposes, e.g. for preventing the appearance of any ghost on the screen of a television or radar receiver, for constructing a darkroom which admits no radiowave, and for making an electromagnetic shield. An absorber which is made of e.g. ferrite or concrete is used for preventing the appearance of a ghost on a television screen. An absorber made of e.g. rubber and ferrite, or rubber and carbon, is used for preventing the appearance of a ghost on a radar screen. A multilayer or pyramid-shaped absorber which is formed from a polystyrene foam and carbon is used for constructing a darkroom admitting no radiowave.
The development of improved radiowave absorbers is desired. They include an absorber having a small thickness, or weight, one which can absorb waves having a wider range of frequencies, and one which can itself be used as a structural material. Although some reduction in weight has already been achieved, it will be necessary to realize an absorber having a by far smaller weight. A radiowave absorber which can be used directly as a strutural member will certainly find a wide scope of use. As a matter of fact, there are a wide variety of demands for different forms of absorbers which can be used as structural members for constructing various kinds of structures. An absorber of the type which can be mixed with various kinds of other materials, such as a paint, a synthetic resin, glass fibers and cement, when it is used, will also be very useful for a wide variety of applications. The radiowave absorbers are also required to have sufficiently high degrees of heat, chemical and weather resistance.